The invention relates to a transmission control device for the open-loop and/or closed-loop control of the operation of an automatic or automated manual transmission of a motor vehicle.
In principle, the open-loop and/or closed-loop control of the operation of an automatic or automated manual transmission is carried out in accordance with a prescribed shifting strategy based on driving status data and/or driver intention data. The shifting strategy is usually designed such that it permits a compromise between economical and sporty driving styles.
Furthermore, it is already known from the prior art that the shifting strategy takes available environmental information into account in such a way that a gear shift from a current actual gear into a target gear is influenced by available environmental information.
For instance, EP 2 419 662 B1 discloses a transmission control device for the open-loop and/or closed-loop control of the operation of an automatic or automated manual transmission of a motor vehicle, wherein, in creating the shifting strategy, the transmission control device considers, inter alia, topography data from within a defined distance away from a current position of the vehicle. For example, if an intersection with a red traffic signal is recognized on the basis of the topography data within the defined distance in front of the vehicle, then a driver intention is internally increased by the transmission control device, and a target engine speed for an upshift in traction mode is suspended so that an upshift to traction mode is not carried out until later.
A method is known from DE 10 2011 080 712 A1 for influencing a transmission shifting strategy of a motor vehicle, in which a shifting reaction is determined for an anticipatory driving strategy that is based on topology data. One embodiment provides that, when an intersection with a traffic signal is detected ahead and when a remaining duration of a current traffic signal phase is detected, a shifting reaction that depends upon the light phase and/or the velocity is determined, i.e. the shifting reaction is determined in consideration of the sum of the information about a light-controlled intersection ahead and the calculated remaining duration of the current light phase. For instance, if the duration of a current green phase is known, then it is possible to calculate whether the time remaining in the current green phase is sufficient for the vehicle to pass through the intersection at its current velocity. If this is the case, then upshift maneuvers are carried out at a lower target engine speed; otherwise, upshifts are suppressed as much as possible. A method of this type presupposes knowledge about the remaining duration of the current traffic signal phase, which represents a challenge at this time due to the traffic infrastructure and the data that are available or that need to be obtained.
The problem addressed by the invention is thus that of providing an improved transmission control device for the open-loop and/or closed-loop control of the operation of an automatic or automated motor vehicle that is oriented to driver intention and that identifies the driver intention based on available environmental information, and reacts accordingly.
This problem is solved by a transmission control device for the open-loop and/or closed-loop control of the operation of an automatic or automated manual transmission of a motor vehicle, wherein a shifting strategy of the transmission control device based on driving status data and/or driver intention data provides open-loop and/or closed-loop control of the operation of the transmission. The shifting strategy of the transmission control device influences a gear shift from a current actual gear into a target gear based on available environmental information data, wherein the transmission control device is configured to take into account available information about the status of a traffic signal, in particular about a change of the status of a relevant traffic signal, when a downshift from a current actual gear into a lower target gear is requested.
The invention is based upon the recognition that, particularly in street traffic, many drivers attempt to accelerate the vehicle quickly during a recognized change in traffic signal phase from green to amber by correspondingly depressing the accelerator pedal in order to be able to pass through the intersection before the traffic signal changes to red. If the driver attempts to release the maximum accelerating power of the vehicle by a so-called kick-down actuation, it is possible that downshifts will be triggered by this kick-down, which can result in a brief interruption in traction. This in turn can lead to passing the traffic signal later as a result of the downshift than would have occurred without a downshift.
The transmission control device according to the invention for the open-loop and/or closed-loop control of the operation of an automatic or automated manual transmission of a motor vehicle is distinguished on this basis, wherein a shifting strategy of the transmission control device based on driving status data and/or driver intention data provides open-loop and/or closed-loop control of the operation of the transmission, and wherein the shifting strategy of the transmission control device influences a gear shift from a current actual gear into a target gear based on available environmental information data, wherein the transmission control device is configured to take into account available information about the status of a traffic signal, in particular about an (upcoming) change of the status of a relevant traffic signal, when a downshift from a current actual gear into a lower target gear is requested.
In the simplest form, any traffic signal located in the driving direction can be considered relevant. If it is possible to designate one traffic signal among multiple traffic signals in the driving direction as one that is relevant to the vehicle, then that traffic signal can be classified as relevant. Likewise, a pedestrian crossing signal located in the driving direction can also be defined as relevant, since these typically end their green phase earlier. Thus situations can arise in which the pedestrian crossing signal has already ended its green phase but in which the traffic signal relevant to vehicles is still displaying green. If the driver perceives the change in the pedestrian crossing signal, then he or she can carry out a kick-down actuation of the accelerator pedal optionally at a point before the traffic signal relevant to the vehicle changes to amber in order to be sure to be able to pass the light and the intersection before the light turns red.
In particular, in an advantageous development of the invention, the transmission control unit can be configured to take into account the available information about the status of a traffic signal, in particular about an (upcoming) change of the status of a relevant traffic signal, when a downshift from a current actual gear into a lower target gear is requested and when an accelerator pedal actuation by the driver signals the maintenance of the velocity or an intention to accelerate.
An intention to accelerate can be recognized and/or signaled, for example, when it is determined that the driver is performing or has performed a kick-down actuation of the accelerator pedal after the green phase has ended. Likewise, a downshift request can be made because of a, or the, same kick-down actuation.
Moreover, the transmission control device can be configured to prevent, at least initially, a requested downshift (in particular a downshift requested by the kick-down actuation of the accelerator pedal) when an actuation of the accelerator pedal by the driver signals an intention to maintain the velocity or to accelerate (in particular in a kick-down actuation of the accelerator pedal performed by the driver) and when information is available that the relevant traffic signal is in an amber phase following a green phase (or when considering a pedestrian crossing signal as a relevant traffic signal in a red phase following a green phase). In other words, the transmission control unit can be designed such that, at first, it can prevent a downshift (including multiple downshift) into a lower gear that is requested on the basis of the driving behavior of the driver or other parameters, especially when it is detected that the driver has not braked and/or has even accelerated the vehicle despite an amber phase following a green phase.
To implement the prevention of a downshift, a so-called downshift preventer, which prevents a downshift, can be employed when an upcoming traffic signal situation is recognized and a downshift is requested. The downshift preventer can basically be employed in this case when an upcoming traffic signal situation (regardless of the phase) is detected or only once a relevant signal change is recognized. The downshift preventer can be maintained until the intersection has been passed and/or until a relevant intersection point has been passed.
When there is a recognized (upcoming) traffic signal situation with a green phase, an advantageous embodiment of the invention provides that the transmission control device can be configured to detect continuously whether or not a downshift would be sensible based on the current acceleration requirements if the green phase were to end at the current point in time. If it is determined that a downshift would not be sensible, since it would lead to passing through the intersection “later” than without a downshift, measures can already be taken at this point to prevent a (later) downshift on the basis of an existing downshift request.
Whether a requested downshift should be performed or prevented in view of the rapid arrival at the traffic signal and/or the rapid passing of the intersection depends definitively upon the current velocity and the distance of the particular vehicle from the traffic signal and/or from a defined intersection point. Accordingly, the transmission control device can advantageously be configured to prevent, at least initially, a requested downshift (in particular a downshift requested by the kick-down actuation of the accelerator pedal) as a function of the current velocity and/or distance between the motor vehicle and the relevant traffic signal when an actuation of the accelerator pedal by the driver signals an intention to maintain the velocity or to accelerate (in particular in a kick-down actuation of the accelerator pedal performed by the driver) and when information is available that the relevant traffic signal is in an amber phase following a green phase (or when considering a pedestrian crossing signal as a relevant traffic signal in a red phase following a green phase).
To this end, the transmission control device can be configured in particular to prevent, at least initially, a requested downshift (in particular a downshift requested by the kick-down actuation of the accelerator pedal) in cases where the distance ahead until the traffic signal or an intersection point assigned to this traffic signal (start, end, middle) can be covered more quickly without a downshift than with a downshift when an actuation of the accelerator pedal by the driver signals an intention to maintain the velocity or to accelerate (in particular in a kick-down actuation of the accelerator pedal performed by the driver) and when information is available that the relevant traffic signal is in an amber phase following a green phase (or when considering a pedestrian crossing signal as a relevant traffic signal in a red phase following a green phase).
To be able to make a qualified statement as to whether a requested downshift should be performed or prevented in view of the rapid arrival at the traffic signal and/or the rapid passing of the intersection, it is necessary to know the respective lengths of time (with and without downshifting) before reaching the traffic signal or before reaching a position that depends upon the traffic signal and/or the associated traffic situation (e.g. beginning of the intersection, middle of the intersection, end of the intersection). To this end, the transmission control device can be designed in an advantageous embodiment to proactively calculate a first length of time required to cover the distance before reaching the traffic signal or an intersection point associated with this traffic signal (e.g. beginning, end or middle of the intersection) without downshifting and/or a second length of time required to cover the distance before reaching the traffic signal or an intersection point associated with this traffic signal with a downshift when an actuation of the accelerator pedal by the driver signals an intention to maintain the velocity or to accelerate (in particular in a kick-down actuation of the accelerator pedal performed by the driver) and when information is available that the relevant traffic signal is in an amber phase following a green phase (or when considering a pedestrian crossing signal as a relevant traffic signal in a red phase following a green phase). In this way, relevant environmental information, especially environmental information affecting the possible acceleration behavior, in particular information about vehicles traveling ahead, can be taken into account when calculating the first and/or second lengths of time. This makes sense, for example, when the road slopes or vehicles are traveling ahead, which influence or prevent a possible maximum acceleration (with or without downshifting).
For the sake of completeness, it should also be noted that, similar to the prevention of a requested downshift, requested upshift operations can also be suppressed in instances where the traffic signal or relevant intersection point can be reached more quickly in this way.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.